Designfax weekly eMagazine

Subscribe Today!

Archives

View Archives

Partners

Manufacturing Center
Product Spotlight

Modern Applications News
Metalworking Ideas For
Today's Job Shops

Tooling and Production
Strategies for large
metalworking plants

Engineer's Toolbox: How to design the optimum hinge

Although many pin styles are available, Coiled Spring Pins are particularly well suited for use in both friction- and free-fit hinges. To achieve optimum long-term hinge performance, designers should observe these helpful design guidelines from SPIROL.
Read the full article.

Innovative new robo welding gun

Comau's newest N-WG welding gun is designed for high-speed spot welding for traditional, hybrid, and electric vehicles, in addition to general industry sectors. It features a patented, single-body architecture that enables rapid reconfiguration between welding types and forces, and it delivers consistent performance across a broad range of applications, including steel and (soon) aluminum welding. It supports both X and C standard gun configurations, has fast arm exchange, and universal mounting options. It is fully compatible with major robot brands and represents a significant advancement in spot welding performance and cost efficiency.
Learn more.

What's a SLIC Pin^®? Pin and cotter all in one!

The SLIC Pin (Self-Locking Implanted Cotter Pin) from Pivot Point is a pin and cotter all in one. This one-piece locking clevis pin is cost saving, fast, and secure. It functions as a quick locking pin wherever you need a fast-lock function. It features a spring-loaded plunger that functions as an easy insertion ramp. This revolutionary fastening pin is very popular and used successfully in a wide range of applications.
Learn more.

Engineering challenge: Which 3D-printed parts will fade?

How does prolonged exposure to intense UV light impact 3D-printed plastics? Will they fade? This is what Xometry's Director of Application Engineering, Greg Paulsen, set to find out. In this video, Paulsen performs comprehensive tests on samples manufactured using various additive processes, including FDM, SLS, SLA, PolyJet, DLS, and LSPc, to determine their UV resistance. Very informative. Some results may surprise you.
View the video.

Copper filament for 3D printing

Virtual Foundry, the company that brought us 3D-printable lunar regolith simulant, says its popular Copper Filamet™ (not a typo) is "back in stock and ready for your next project." This material is compatible with any open-architecture FDM/FFF 3D printer. After sintering, final parts are 100% pure copper. Also available as pellets. The company says this is one of the easiest materials to print and sinter. New Porcelain Filamet™ available too.
Learn more and get all the specs.

Copper foam -- so many advantages

Copper foam from Goodfellow combines the outstanding thermal conductivity of copper with the structural benefits of a metal foam. These features are of particular interest to design engineers working in the fields of medical products and devices, defense systems and manned flight, power generation, and the manufacture of semiconductor devices. This product has a true skeletal structure with no voids, inclusions, or entrapments. A perennial favorite of Designfax readers.
Learn more.

Full-color 3D-printing Design Guide from Xometry

With Xometry's PolyJet 3D-printing service, you can order full-color 3D prints easily. Their no-cost design guide will help you learn about different aspects of 3D printing colorful parts, how to create and add color to your models, and best practices to keep in mind when printing in full color. Learn how to take full advantage of the 600,000 unique colors available in this flexible additive process.
Get the Xometry guide.

Tech Tip: How to create high-quality STL files for 3D prints

Have you ever 3D printed a part that had flat spots or faceted surfaces where smooth curves were supposed to be? You are not alone, and it's not your 3D printer's fault. According to Markforged, the culprit is likely a lack of resolution in the STL file used to create the part.
Read this detailed and informative Markforged blog.

Test your knowledge: High-temp adhesives

Put your knowledge to the test by trying to answer these key questions on how to choose the right high-temperature-resistant adhesive. The technical experts from Master Bond cover critical information necessary for the selection process, including questions on glass transition temperature and service temperature range. Some of the answers may surprise even the savviest of engineers.
Take the quiz.

Engineer's Toolbox: How to pin a shaft and hub assembly properly

One of the primary benefits of using a coiled spring pin to affix a hub or gear to a shaft is the coiled pin's ability to prevent hole damage. Another is the coiled pin absorbs wider hole tolerances than any other press-fit pin. This translates to lower total manufacturing costs of the assembly. However, there are a few design guidelines that must be adhered to in order to achieve the maximum strength of the pinned system and prevent damage to the assembly.
Read this very informative SPIROL article.

What's new in Creo Parametric 11.0?

Creo Parametric 11.0 is packed with productivity-enhancing updates, and sometimes the smallest changes make the biggest impact in your daily workflows. Mark Potrzebowski, Technical Training Engineer, Rand 3D, runs through the newest functionality -- from improved surface modeling tools to smarter file management and model tree navigation. Videos provide extra instruction.
Read the full article.

What's so special about wave springs?

Don't settle for ordinary springs. Opt for Rotor Clip wave springs. A wave spring is a type of flat wire compression spring characterized by its unique waveform-like structure. Unlike traditional coil springs, wave springs offer an innovative solution to complex engineering challenges, producing forces from bending, not torsion. Their standout feature lies in their ability to compress and expand efficiently while occupying up to 50% less axial space than traditional compression springs. Experience the difference Rotor Clip wave springs can make in your applications today!
View the video.

New Standard Parts Handbook from JW Winco

JW Winco's printed Standard Parts Handbook is a comprehensive 2,184-page reference that supports designers and engineers with the largest selection of standard parts categorized into three main groups: operating, clamping, and machine parts. More than 75,000 standard parts can be found in this valuable resource, including toggle clamps, shaft collars, concealed multiple-joint hinges, and hygienically designed components.
Get your Standard Parts Handbook today.

Looking to save space in your designs?

Watch Smalley's quick explainer video to see how engineer Frank improved his product designs by switching from traditional coil springs to compact, efficient wave springs. Tasked with making his products smaller while keeping costs down, Frank found wave springs were the perfect solution.
View the video.

Top die casting design tips

You can improve the design and cost of your die cast parts with these top tips from Xometry's Joel Schadegg. Topics include: Fillets and Radii, Wall Thicknesses, Ribs and Metal Savers, Holes and Windows, Parting Lines, and more. Follow these recommendations so you have the highest chance of success with your project.
Read the full Xometry article.

New plant-derived composite is tough as bone and hard as aluminum alloys

A new woody composite, engineered by a team at MIT, is tough as bone and hard as aluminum, and it could pave the way for naturally derived plastics. This image shows a tooth printed by the team resting on a background of wood cells. [Credit: Figure courtesy of the researchers/MIT]

 

 

 

 

By Jennifer Chu, MIT

The strongest part of a tree lies not in its trunk or its sprawling roots, but in the walls of its microscopic cells.

A single wood cell wall is constructed from fibers of cellulose ­-- nature's most abundant polymer, and the main structural component of all plants and algae. Within each fiber are reinforcing cellulose nanocrystals, or CNCs, which are chains of organic polymers arranged in nearly perfect crystal patterns. At the nanoscale, CNCs are stronger and stiffer than Kevlar. If the crystals could be worked into materials in significant fractions, CNCs could be a route to stronger, more sustainable, naturally derived plastics.

Now, an MIT team has engineered a composite made mostly from cellulose nanocrystals mixed with a bit of synthetic polymer. The organic crystals take up about 60 to 90% of the material -- the highest fraction of CNCs achieved in a composite to date.

The researchers found the cellulose-based composite is stronger and tougher than some types of bone, and harder than typical aluminum alloys. The material has a brick-and-mortar microstructure that resembles nacre, the hard inner shell lining of some mollusks.

The team hit on a recipe for the CNC-based composite that they could fabricate using both 3D printing and conventional casting. They printed and cast the composite into penny-sized pieces of film that they used to test the material's strength and hardness. They also machined the composite into the shape of a tooth to show that the material might one day be used to make cellulose-based dental implants -- and for that matter, any plastic products -- that are stronger, tougher, and more sustainable.

"By creating composites with CNCs at high loading, we can give polymer-based materials mechanical properties they never had before," says A. John Hart, professor of mechanical engineering. "If we can replace some petroleum-based plastic with naturally derived cellulose, that's arguably better for the planet as well."

Hart and his team, including Abhinav Rao PhD '18, Thibaut Divoux, and Crystal Owens SM '17, have published their results in the journal Cellulose.

Gel bonds
Each year, more than 10 billion tons of cellulose is synthesized from the bark, wood, or leaves of plants. Most of this cellulose is used to manufacture paper and textiles, while a portion of it is processed into powder for use in food thickeners and cosmetics.

In recent years, scientists have explored uses for cellulose nanocrystals, which can be extracted from cellulose fibers via acid hydrolysis. The exceptionally strong crystals could be used as natural reinforcements in polymer-based materials. However, researchers have only been able to incorporate low fractions of CNCs, as the crystals have tended to clump and only weakly bond with polymer molecules.

The team hit on a recipe for the CNC-based composite that they could fabricate using both 3D printing and conventional casting. [Credit: Figure courtesy of the researchers]

 

 

 

 

Hart and his colleagues looked to develop a composite with a high fraction of CNCs that they could shape into strong, durable forms. They started by mixing a solution of synthetic polymer with commercially available CNC powder. The team determined the ratio of CNC and polymer that would turn the solution into a gel, with a consistency that could either be fed through the nozzle of a 3D printer or poured into a mold to be cast. They used an ultrasonic probe to break up any clumps of cellulose in the gel, making it more likely for the dispersed cellulose to form strong bonds with polymer molecules.

They fed some of the gel through a 3D printer and poured the rest into a mold to be cast. They then let the printed samples dry. In the process, the material shrank, leaving behind a solid composite composed mainly of cellulose nanocrystals.

"We basically deconstructed wood, and reconstructed it," Rao says. "We took the best components of wood, which is cellulose nanocrystals, and reconstructed them to achieve a new composite material."

Tough cracks
Interestingly, when the team examined the composite's structure under a microscope, they observed that grains of cellulose settled into a brick-and-mortar pattern, similar to the architecture of nacre. In nacre, this zig-zagging microstructure stops a crack from running straight through the material. The researchers found this to also be the case with their new cellulose composite.

They tested the material's resistance to cracks, using tools to initiate first nano- and then micro-scale cracks. They found that, across multiple scales, the composite's arrangement of cellulose grains prevented the cracks from splitting the material. This resistance to plastic deformation gives the composite a hardness and stiffness at the boundary between conventional plastics and metals.

Going forward, the team is looking for ways to minimize the shrinkage of gels as they dry. While shrinkage isn't much of a problem when printing small objects, anything bigger could buckle or crack as the composite dries.

"If you could avoid shrinkage, you could keep scaling up, maybe to the meter scale," Rao says. "Then, if we were to dream big, we could replace a significant fraction of plastics with cellulose composites."

Published March 2022

Rate this article